I presume this is for your Shuttle AK31A ver.3.1 rig,anyway do you`ve the VIA 4 in 1 drivers installed,also get the latest drivers for monitor & your onboard sound,some bios tweaks might help,disable video ram cacheable,disable system bios cacheable,disable all video shadowing, last resort would be to try and run in 2x AGP mode(you shouldn`t need too),btw do any of your games run fine & what PSU are you using?